In the CNN Republican Debate, Donald Trump made the claim that vaccines cause autism. “Autism has become an epidemic. Twenty-five years ago, 35 years ago, you look at the statistics, not even close. It has gotten totally out of control,” Trump said. “I am totally in favor of vaccines. But I want smaller doses over a longer period of time. Same exact amount, but you take this little beautiful baby, and you pump—I mean, it looks just like it’s meant for a horse, not for a child, and we’ve had so many instances, people that work for me.” Trump claimed that if vaccines were spread out, a little at a time, “I think you’re going to see a big impact on autism.”

Ben Carson and Rand Paul each hold an M.D. so I had hope that they would shoot Mr. Trump down and put a stop to two baseless myths about vaccines. Instead, Dr. Carson said that there is proof that autism is not associated with vaccines but “we are probably giving way too many in too short a period of time.” Rand Paul followed suit saying, “Even if the science doesn’t say bunching them up is a problem, I ought to have the right to spread out my vaccines a little bit at the very least.” Refusing to stand up to unsubstantiated myths about lifesaving vaccines is a disgrace to the medical profession and dangerous for the population – but that’s for another post.

Vaccines do not cause autism. In the scientific and medical communities, there is no debate on this issue because the data are clear. You can ask the Centers for Disease Control and Prevention, the National Institutes of Health, the American Academy of Pediatrics, the World Health Organization, and the Institute of Medicine (to name a few) and they will tell you that, whether administered alone or grouped together, vaccines do not cause autism. The CDC maintains an excellent page here that goes into great detail about the safety of vaccines and the research that has been conducted to determine whether vaccines play any role in the development of autism.

What about Donald Trump’s second position? I can understand why it might seem disconcerting to inject your child with a handful of vaccines all at once. What we must keep in mind, however, is that our personal feelings do not determine what is true. Let’s think about how many bacteria and viruses a child is exposed to in the course of an average minute:

In each cubic meter of air, there are between 1.6 million and 40 million viruses. In each cubic meter of air, there are between 860,000 and 11 million bacteria. A child inhales about 5 liters of air per minute (or about .005 cubic meters), so a few hundred thousand viruses and bacteria are inhaled every minute every day of the year. Researchers discovered that many were unknown species of viruses and bacteria, so the immune system has to adapt to them with each breath. [1] [2]

How many antigens is a child exposed to (by immunizations) by the age of two? Approximately 153.

While children are receiving more immunizations by the age of two, they are actually receiving less antigens, or bits of the vaccine that would challenge the immune system. Overall numbers of antigens have fallen from about 3,041 in 1980 to approximately 153 today. [3]

What’s the takeaway here?

Current studies do not support the hypothesis that multiple vaccines overwhelm, weaken, or “use up” the immune system. On the contrary, young infants have an enormous capacity to respond to multiple vaccines, as well as to the many other challenges present in the environment. By providing protection against a number of bacterial and viral pathogens, vaccines prevent the “weakening” of the immune system and consequent secondary bacterial infections occasionally caused by natural infection. [4] In the face of these normal events, it seems unlikely that the number of separate antigens contained in childhood vaccines … would represent an appreciable added burden on the immune system that would be immunosuppressive. [5]

You may be asking, “Well, is there any harm to spreading the vaccines out over a longer period of time?”

Yes. According to the American Academy of Pediatrics: “Each vaccine dose is scheduled using 2 factors. First, it is scheduled for the age when the body’s immune system will work the best. Second, it is balanced with the need to provide protection to infants and children at the earliest possible age.” The consequence of delaying vaccine doses is an increased risk to the health and well-being of your child. The AAP continues:

First, you would not want your child to go unprotected that long. Babies are hospitalized and die more often from some diseases, so it is important to vaccinate them as soon as it is safe. Second, the recommended schedule is designed to work best with a child’s immune system at certain ages and at specific times. There is no research to show that a child would be equally protected against diseases with a very different schedule. Also, there is no scientific reason why spreading out the shots would be safer. But we do know that any length of time without immunizations is a time without protection. [6]

So, does the evidence support any of Donald Trump’s claims? The answer is a resounding NO.